At least I know where the *big* hand is...April 6, 2006 3:43 PMSubscribe

If you live or work near a time zone line, how is life different for you and what difficulties have you run into? A more specific sub-question involving cell phones included...

This started as a discussion with my boss. We were talking about cell phones picking up the local time from the network, and were wondering how this was handled near the time zone borders. Does your phone show a different local time throughout the day as you move from place to place and associate with different towers? How does that affect you when, say, your free night minutes start at 9pm?

Other than cell phones, I'm also curious about any other "special" things people have to account for when near these borders. Do you get used to keeping track of which side of the line you're on, and it becomes routine?

Having spent quite a few years in the South Bend In. Niles Mi. area and living and working on both sides of the state line, going opposite directions both ways, I'll say you get very used to it. With Indiana, until this year, being the 'don't change the clocks state' it was even more confusing because rules only applied half the year.
Now that I live in Michigan and regularly travel back to Indiana I can say that at least on the route I take the time switch on my clock is within .5 to 1 mile of the state line. I would assume that the minutes are a factor of the local time where call is originated but that is a guess.
I tended to keep my watch on work time and left the house clocks on the local time. Other than that nothing special.
The thing with time zones is the change in the sun location. After moving to the eastern end of Long Island the one thing I could never get used to was how early the sun did everything, rise in the summer and set in the winter. Long Island being the Eastern part of the Eastern zone and Michigan being the western for an offset of about 1 hour. I always said that eastern Long Island should be 1 time zone further east. No one agreed with me for some reason.posted by mss at 4:29 PM on April 6, 2006

I agree. The sun sets way too early out here (especially in the winter - 4:30 p.m.)posted by fuerloins at 4:32 PM on April 6, 2006

I live near a dividing line myself. I do take care to ensure that when working across the line any calendar entries specify both my time and the adjoining time - e.g., "Meet with Paul Smith, 10 a.m. (9 a.m. PT)" - so that there is no confusion. That was after one or two episodes of being an hour early - or an hour late.

The time zone dance makes for interesting issues when daylight savings time trips on or off. On one highway, I cross from MT to PT and vice versa. I tell friends that, if you are traveling on that road on the key Sunday morning at 2 a.m., and happen to cross the line right at 2, when the time changes, you will meet yourself coming the other way. If you are traveling in the other direction, you will disappear from the face of the earth - for an hour.posted by megatherium at 6:45 PM on April 6, 2006

Not strictly on topic, but I recall one of the TWiTs mentioning that they got their cell phone on a trip to Rhode Island, even though they live in California, so their "Nights and Weekends" start hours earlier.posted by Rock Steady at 6:57 PM on April 6, 2006

Care to read more than you want to know about how IS-95 handles time? That's what I used to work on when I was at Qualcomm.

IS-95 is the standard that Verizon uses. J-STD-008 (Sprint) is virtually the same.

You asked about billing (e.g. day rates, night rates). That's based on the time zone that the cell system central office is in. The cell central office system doesn't care what time your phone thinks it is and it doesn't care where you are physically located; it only cares what the GPS receiver connected to it says the time is.

An IS-95 phone figures out the time when it "acquires" a system. Nerd details: Step 1 of acquisition is to find the pilot, which initializes the short code generator. Step 2 is to find and read the Sync Channel Message, which tells the phone the time of day accurate to a fraction of a microsecond (discounting speed-of-light phase delay). That's used to initialize the long code generator. Then step 3 is to read a message off the paging channel in order to find out what cell system the phone has found. The cell system identification code is then looked up in the phone's PRL, and based on that the phone either register or goes back to searching for another system which is better. End of nerd details.

The time gotten from the Sync Channel Message gets used to set the phone's internal time-of-day clock, which is what it displays when it doesn't have anything more important to display. But that time is there simply for your convenience. It has no significance at all for the cell system.

The phone doesn't do a full acquisition when it hands off from one cell or sector to another within the same system (idle handoff or soft handoff). But it does when it switches from one system to another. If there are two systems on opposite sides of a time zone, and you drive from one to the other, the time displayed will change because the phone's time-of-day clock will get reset as part of system acquisition.

But if you're on one side of a timezone line and the cell system central office whose cell your talking to is on the other side, you will be billed according to the time that the cell system thinks it is, not according to where you are physically located.posted by Steven C. Den Beste at 8:10 PM on April 6, 2006

The thing I'd be more worried about is a situation like the following:
Once, I was on the Detroit side of Lake St. Clair, and a good number of the people I was with were getting "Welcome to Bell Wireless" messages. I'm guessing they'd have been charged for roaming in Canada despite not being in Canada.posted by oaf at 8:50 PM on April 6, 2006

Yes, that's the case. It doesn't matter where you are; all that matters is where the cell system thinks it is.posted by Steven C. Den Beste at 9:09 PM on April 6, 2006

Last summer we were on the Lake Michigan beach on the Michigan side and my sisters' cell phone switched to Central time.

We were an hour late for dinner.posted by Floydd at 6:42 AM on April 7, 2006

We've had the problem with cells connecting to out of country towers the last couple of times we've hosted conferences in Niagara Falls. They pick up the towers across the river, and everyone gets slammed with huge roaming fees. This year, they sent out instructions (which I didn't actually read, because I didn't even take my cell) on how to lock the cell to not roam on other networks. If you're frequently in that situation, oaf, you might consider asking your provider if there's an option like that for your phone.posted by jacquilynne at 7:37 AM on April 7, 2006

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